Pump.



C. W. TARBET.

PUMP.

APPLICATION F'ILED DEC. 3|. 1914.

1 ,206,94:3 4 Patented Dec. 5, 1916.

i are now on the market,

. time, the loss of time being of -overheated when Unirnn STATES PATENT OFFICE.

CLARENCE W. TARBET, OF CHICAGO, ILLINOIS.

PUMP.

Specification of Letters Patent.

Patented Dec. 5, 1916.

Application filed December 31, 1914. Serial No. 879,843. 1

To all whom it may concern:

Be it known that I, CLARENCE W. TARBET, a citizen of the United States, residing in the city of Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Pumps, -of which the following is aspecificationl I My invention relates to improvements in pumps and, although it has many applications, it is particularly well fitted, for emg the arduous labor of pumpmg up the tires by hand. In some cases in place of usinga power-driven pump, the car is equipped with a storage tank containing a supply of air or other suitable gas under a very high pressure, but this arrangement, while very convenient while the tank is charged, necessitates frequent replacement of the empty tanks with full ones, and, in addition, intro duces the dangerrof being caught with an empty tank far from home, when tiretrou- For this reason, most people ble develops. prefer to equip the cars with air-pumps.

j Of the pumps of the type described which the great majority, although of considerable Weight and bulk, are of limited capacity and consequently unable to pump up a deflated tire to the proper pressure in a reasonable length of coursevery marked'when it is necessary to inflat a tire which for any reason may have become completely deflated. On the other hand, the few air-pumps on the market which are power-driven capable of supplying a suflicient amount of L air andpressure to inflate a tire/with reasonable speed, are usually of excessive weight and bulk and often extremely intricate in design. Many of these pumps also are open to the objection of becoming greatly they are operated at the desired speed. Other pumps also have the particularly vicious "habit of exhaling lubrieating oil which thus results in a gradual purpose of replenishing the line deterioration or disintegration of the rubber after the oil is forced into the tire.

The objects of my invention are, to pro vide a pump of the class described which may be constructed of comparatively large capacity, while at the same time of comparativelysmall weight and dimensions; to provide a pump of the cla'ssdescribed which maybe operated at high speed-without danger of overheating; to provide a pump of the class described in which there is no fear of contaminating the fluid under pressure with the oil used to lubricate the worln'ng parts of the pump; to provide a pump which may be constructed of a comparaof parts, and those of 1 tively small number simple and rugged form; to provide a construction in which the working parts are so designed as to operate for an indefinite period without renewal of any of the bearing surfaces or other parts; to provide a pump which may be economically constructed in largequantities by means of automatic machinery, and, in general, to provide an improved pump of the class described.

In the drawings illustrating an approved embodiment of my invention'Figure1 is a sectional plan View of an automobile airpump constructed according to my inven-.;'

tion; Fig. 2 is a section of Fig. 1 taken on 22 of Fig. 1; and Fig. 3 is a fragmentary section takenronthe line 3-3 of Fig. 2.

' As showing the application of my invention, I have selected as an illustration a pump capable of being mounted upon any fixed part of the frame ofan automobile and adapted to be driven from. some moving part of the chassis equipment. In'the drawings the main casing or frame of the pump 10 also constitutes the cylinder of the device in whichis double-acting piston 11. In one side of the casing or cylinder, which is an integral casting of bronze, cast iron, or other suitable material, is formed an integral base or foot 12 which is adapted to be bolted or other-- wise secured to theframe of the chassis or to the motor. The ends of the cylinder are completely incased by means of a pair of heads 13 which, are securely bolted-to the turned ends of'the cylinder by means of a adapted to reciprocate a imum extent.

' .which the outer end be observed that I have made these valves 15 and 16 of extremely large area and consequent high capacity, so that the air passing through them will be throttled to a min- This throttling of the air through the valves is highly objectionable in pumps of this type, since it is often desirable to operate them at very high speed,

and if the air passages are constricted, the difl'erence pressure between the air in the cylinder and the air on the other side of the valve is excessive and is apt to cause serious overheating. The exit valves 15 are connected by short L-shaped pipes which make a connection with a T 18 and the common pressure pipe 19 fitted thereon.

Describing the piston 11 in the cylinder 10, it will be seen that the piston consists of an extended piece of metal of cylindrical shape, which is imperforate longitudinally as regards its two ends, but in its center is cut out or slotted to form a transverse rectangular aperture extending diametrically from one side of the piston to the other. The distance apart of the adjacent ends of the slot in a longitudinal direction is such asto accommodate with proper fr'efilom the cam or eccentric 21, keyed, or otherwise suitably secured, to the transverse operating sha 22. This main shaft 22 also extends transversely across and diametrically of the cylinder and piston and is centrally located therein. The inner end of the shaft 22 is reduced slightly in its diameter so as to form a journal 22 which enters an inwardly opening cylindrical bore formed in a small boss 23 at the side and in the middle of the cylinder 10. The

opposite wall of the cylinder 10, through of said shaft 22 passes, is provided with a slight circular enlargement 24, which is bored out centrally of the shaft with a large hole threaded to accommodate a plug 25. The inner diameter of said large hole is great enough to admit the eccentric 21' when assembling the pump, the

axial length of the journal 22 being relatively short so as to obviate the danger of the eccentric 21 striking the wall of the cylinder before the journal becomes disengaged. The bushing 26, the outer end of which is threaded to enter the annular plug 25, constitutes a bearing for the outer end of the shaft and also limits'the axial movement thereof, since the inner end of the bearing 26 is extended until it engages the outer end face of the eccentric 21. On the outer end of the shaft 22 I mount a clutch a member 27'. which is adapted to slide upon :the, shaft, rotation thereof with reference to the shaft, being prevented by means'of a key the means for reciprocatingthe pump is operated.

28 seated in the exterior of said shaft. This clutch member 27 normally is in the position shown in Fig. 2, with its back end face in substantial contact with the outer face .of the shoulder 29 on the end of-the bushing 26; but when it is desired .to operate the pump, it is moved endwise axially of the shaft and away from the cylinder 10 so as to engage a companion clutch member 30 formed on the inner end face of the hub of a chain or sprocket wheel 31, which is continuously driven from the motor by means of a silent chain 32, and rotates freely on the shaft 22. In order to facilitate the shift ing of the clutch member 27 into or'out of engagementvwith the clutch member 30, I

turnin its exterior a rectangular groove 33 in which ride a pair of diametrically opwhen the pump is not in use, the chain wheel 31 rotating idly upon the end of the shaft 22. When, however, the clutch fork 36 is shifted so as to bring the clutch members 27 and 28 into engagement, the shaft commences to rotate and with it the eccentric. The eccentric 21, being of proper.

diameter to suitably engage the ends of the slot 20 as it rotates, thus causes a reciprocatory movement ofthe It should be noticed that although, theoretically speaking, the Wearing surface between the eccentric 21 and the ends of the slot 20 is a line contact, it should nevertheless be understood that this line contact is continually moving transversely of the cylinder to and fro across the wearing surface of the slot; consequently, lubrication is very effective and frictional wear is reduced to a. negligible quantity.

In order to prevent oil from becoming mixed with and contaminating the air under pressure before it enters the tires of the car, I interpose between each end of the piston and the cylinder head a diaphragm $0 of suitable flexible material, such as leather or composition rubber fabric, which is clamped in an annular space 41 provided between the cylinder head and the end of the cylinder. The center of the diaphragm is secured to the center of the end of the piston by means of a washer 42 held by a flat-head screw 13 tapped into the center of the piston. The end of the piston adjacent to and around its center is tened under the washer 42, but the remainpiston 11, and thus ing portion of its operating face is formed in the shape of a portion of a sphere so as to enter and fill a similar spherical cavity or swell formed in the inner face of each of the cylinder heads. The washer 42 and screw 43 are similarly turnedoff in spherical shape so as to enter the central portion of said spherical cavity in the cylinder head; and the dimensions of all of these parts and the stroke of the piston are such that when the latter reaches its extreme limit of outward movement, the end of the piston, diaphragm, and cylinder head are e substantially in contact with each other, thus .the normal plane of the diaphragm.

1 pressure in the end of the eliminating all clearance spaces, the presence of which would seriously interfere with the efiiciency of the pump. It should be noted that the spherical shape of the piston end and cylinder head also tends to reduce the amount of bending of the diaphragm 40, since the point of attachment of the center of the diaphragm to the piston alternates in position an equal distance on either side of It should also be noted that during the time that the diaphragm is largely without support from the end of the piston 11, the air cylinder cavity is comparatively slight, but when the air becomes compressed within the end of the cylinder during the. final portion of the outward movement of the piston, the diaphragm is supported by the end of the piston over substantially its entire area, this being clearly shown in'the upper portion of Fig. 1. Obviously, it makes little difl'erence whether the working parts of the pump are over-supplied with oil or not, since such oil, even if it does work through between the piston and the cylinder head, cannot pass through the diaphragms 40, and thus the air compressed by the pump retains its original purity.

It will be manifest that the construction described is extremely rugged and substantial and free from complicated parts or mechanism. The provision of the diaphragms at the ends of the piston also enables me to make the piston a comparatively loose fit within the cylinder, since with the diaphragms there is no object in having airproof engagement between the wall of the piston and the cylinder. Thus, by the elimination of the customary spring rings and tight fitting engagement between said parts, which are necessary in ordinary pumps constructed without diaphragms, Iam enabled to reduce to a minimum the friction of the piston sliding within the cylinder. Although I have shown the cylinder heads as being secured to the cylinder in such manner as to cause the exit pipes to project sidewise from the frame, yet it should be understood that the position of the heads may be changed readily by means of the screws with which'said heads are clamped to the ends of the cylinder. Thus, the pump which, in itself is extremely compact, ma}

be arranged for application in any desired location on the engine or frame of the car.

Although I have described what I considerto be a preferred embodiment showing the application of my invention to a pump of the class described, yet it should be understood that many details of my construc-.

cylindrical piston of sufficient length to prevent cramping, adapted to reciprocate in said cylinder between said heads and provided with an aperture extending diametrically through the piston intermediate the ends of the latter, a shaft diametrically arranged to rotate within said cylinder extending through the aperture of said piston andprovided with an eccentric adapted to engage said piston; said piston having comparatively loose fitting engagement with said cylinder,'and flexible diaphragms interposed between the ends of said cylinder and said piston.

CLARENCE W. TARBET. Witnesses:

G. A. SoANs, EMILIE Rosn. r 

